1. Technical Field
The present invention relates to an image forming apparatus which forms an image by scanning a light beam on a surface of a latent image carrier in a main scanning direction substantially perpendicular to the sub scanning direction, the latent image carrier driven in a sub scanning direction. The invention also relates to an image forming method used in the apparatus.
2. Related Art
The image forming apparatus of this type includes the latent image carrier, an exposure unit and a developer unit and operates as follows to form a toner image on the latent image carrier. Specifically, a light source of the exposure unit is controlled based on image data representing the toner image. In the meantime, the exposure unit makes a deflector deflectively scan the light beam from the light source in the main scanning direction as focusing the light beam in a spot shape on the latent image carrier, whereby a latent image corresponding to the image data is formed on the surface of the latent image carrier. Then, the latent image is developed with toner to form the toner image.
JP A-2002-182147 proposes an art to use an oscillatory deflection mirror surface as the deflector in order to achieve the downsizing and high speed performance of the deflector. In this apparatus, the deflection mirror supported by a torsion bar is brought into oscillation, while the light beam emitted from the light source is reflected by the deflection mirror for reciprocally scanning the light beam on the surface of the latent image carrier.